Conventional magnetic resonance imaging (MRI) involves using similar to identical acquisition blocks over and over. For example, in repetitive acquisition blocks, repetition time (TR) may be the same, gradients other than the phase encoding gradient may be held constant, and other parameters may be identical. The repetitive identical or similar acquisition blocks may induce significant vibrations in the MRI scanner hardware. These vibrations may cause significant, undesirable sounds that may manifest themselves as clicks or even what patients describe as “banging”. Loud, repetitive banging is a significant patient complaint about MRI.
Conventional magnetic resonance (MR) pulse sequences include a preparation phase, a waiting phase, and an acquisition phase that are configured to produce signals from which images can be made. The preparation phase determines when a signal can be acquired and determines the properties of the acquired signal. For example, a first pulse sequence may be designed to produce a T1-weighted signal at a first echo time (TE) while a second pulse sequence may be designed to produce a T2-weighted signal at a second TE. T1 is spin-lattice relaxation and T2 is spin-spin relaxation. A conventional MR acquisition involves numerous repetitions of prepare/wait/acquire pulse sequences. For example, the first pulse sequence may be applied a large number of times to acquire T1 weighted signals for all voxels in a volume of interest (RoI) and then the second pulse sequence may be applied a large number of times to acquire T2 weighted signals for all the voxels in the RoI. When these preparations and waits are repeated under similar to identical conditions over and over, the repetitive actions may lead to undesirable sound effects for the patient in the MRI apparatus.